The present invention relates to spirocyclic cyclohexane derivatives, processes for their preparation, medicaments comprising these compounds and the use of spirocyclic cyclohexane derivatives for the preparation of medicaments.
The heptadecapeptide nociceptin is an endogenous ligand of the ORL1 (opioid receptor-like) receptor (Meunier et al., Nature 377, 1995, p. 532-535), which belongs to the family of opioid receptors and is to be found in many regions of the brain and spinal cord, and has a high affinity for the ORL1 receptor. The ORL1 receptor is homologous to the μ, κ and δ opioid receptors and the amino acid sequence of the nociceptin peptide has a marked similarity to those of the known opioid peptides. The receptor activation induced by nociceptin leads, via coupling with Gi/o proteins, to an inhibition of adenylate cyclase (Meunier et al., Nature 377, 1995, p. 532-535).
The nociceptin peptide shows a pronociceptive and hyperalgesic activity after intercerebroventicular administration in various animal models (Reinscheid et al., Science 270, 1995, p. 792-794). These findings can be explained as an inhibition of stress-induced analgesia (Mogil et al., Neuroscience 75, 1996, p. 333-337). In this connection, it has also been possible to demonstrate an anxiolytic activity of nociceptin (Jenck et al., Proc. Natl. Acad. Sci. USA 94, 1997, 14854-14858).
On the other hand, it has also been possible to demonstrate an antinociceptive effect of nociceptin in various animal models, in particular after intrathecal administration. Nociceptin has an antinociceptive action in various pain models, for example in the tail flick test in the mouse (King et al., Neurosci. Lett., 223, 1997, 113-116. It has likewise been possible to demonstrate an antinociceptive action of nociceptin in models for neuropathic pain, which is of particular interest inasmuch as the activity of nociceptin increases after axotomy of spinal nerves. This is in contrast to conventional opioids, the activity of which decreases under these conditions (Abdulla and Smith, J. Neurosci., 18, 1998, p. 9685-9694).
The ORL1 receptor is moreover also involved in regulation of further physiological and pathophysiological processes. These include, inter alia, learning and memory development (Manabe et al., Nature, 394, 1997, p. 577-581), audition (Nishi et al., EMBO J., 16, 1997, p. 1858-1864) and numerous further processes. A review article by Cabo et al. (Br. J. Pharmacol., 129, 2000, 1261-1283) gives an overview of the indications or biological processes in which the ORL1 receptor plays a role or with high probability could play a role. This mentions, inter alia: analgesia, stimulation and regulation of food intake, influence on μ-agonists, such as morphine, treatment of withdrawal symptoms, reduction in the addiction potential of opioids, anxiolysis, modulation of motor activity, impaired memory, epilepsy; modulation of neurotransmitter secretion, in particular glutamate, serotonin and dopamine, and therefore neurodegenerative diseases; influencing of the cardiovascular system, initiation of an erection, diuresis, anti-natriuresis, electrolyte balance, arterial blood pressure, water retention diseases, intestinal motility (diarrhea), relaxing effects on the respiratory tract, micturation reflex (urinary incontinence). The use of agonists and antagonists as anoretics, analgesics (also in co-administration with opioids) or nootropics is furthermore discussed.
The possible uses of compounds which bind to the ORL1 receptor and activate or inhibit this are correspondingly diverse. Alongside this, however, opioid receptors, such as the μ-receptor, but also the other sub-types of these opioid receptors, namely δ and κ, play a large role precisely in the area of pain therapy, but also in that of other indications of those mentioned. Accordingly, it is favourable if the compound also show an action on these opioid receptors.